The Olsen twins have been breaking the law - by chain smoking at business meetings.Mary-Kate and Ashley, once known for their wholesome image, use their fame to market themselves as a brand through their billion dollar company Dualstar Entertainment Group.The twins visit Dualstar's Culver City offices in California once a month, where they allegedly chain smoke for hours in their office.According to California law, smoking indoors in public places is illegal.The Olsens, who turn 20 this month, have been child actors since they were one and after becoming a household name in the US, were dubbed the 'Wholesome Olsens'.But Mary-Kate shattered their clean image when she checked into rehab to be treated for an eating disorder, and was plagued by rumours she had a drug addiction.